[Python-Dev] Classes and Metaclasses in Smalltalk

[M.-A. Lemburg]

Greg Ewing wrote:
> 
> "M.-A. Lemburg" <mal@lemburg.com>:
> 
> > I think it has to do with terminology: when I say "inherit"
> > I actually mean "the lookup is forwarded to the another object".
> 
> Some OO languages munge together the instance and inheritance
> relationships, but Python isn't one of them. Using terminology
> that way in the context of Python is guaranteed to cause
> massive confusion!

But that's exactly what I am trying to do here: separate the
notion of how lookups work (inheritance) from how objects are 
created (instantiation) !

In Python instantiation binds the new object to the creating
class and all failing lookups are directed from the object to
the class. 

OTOH, the class - base-class lookup relationship 
doesn't have anything to do creation of objects -- classes
are simply bound to their base-classes per definition of the
class in the sense that failing lookups are directed to the
base-classes.

Classes themselves are created by meta-classes. The lookup
strategy between the two is defined by the meta-class.

What I'm argueing for is that meta-classes should get complete
control over how lookups and object creation are done. However,
this will only be possible by breaking the current automatic
lookup scheme at the meta-class - class boundary since otherwise
you'd run into endless loops during lookups (e.g. for many of
the __xxx__ methods).

-- 
Marc-Andre Lemburg
______________________________________________________________________
Company & Consulting:                           http://www.egenix.com/
Python Software:                        http://www.lemburg.com/python/